<title>小球</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cm">/*</span>
<span class="pl-cm">20 524288</span>
<span class="pl-cm">*/</span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstdio&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;bitset&gt;</span><span class="pl-cp"></span>
<span class="pl-k">using</span> <span class="pl-k">namespace</span> <span class="pl-n">std</span><span class="pl-p">;</span>
<span class="pl-n">bitset</span><span class="pl-o">&lt;</span><span class="pl-mi">3000000</span><span class="pl-o">&gt;</span> <span class="pl-n">tree</span><span class="pl-p">;</span>
<span class="pl-kt">int</span> <span class="pl-n">d</span><span class="pl-p">,</span><span class="pl-n">bi</span><span class="pl-p">;</span>
<span class="pl-kt">int</span> <span class="pl-nf">go</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">root</span><span class="pl-p">,</span><span class="pl-kt">int</span> <span class="pl-n">step</span><span class="pl-p">){</span>
	<span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">step</span><span class="pl-o">&gt;=</span><span class="pl-n">d</span><span class="pl-p">)</span><span class="pl-k">return</span> <span class="pl-n">root</span><span class="pl-p">;</span>
	<span class="pl-k">else</span> <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">tree</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">]){</span>
		<span class="pl-n">tree</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span>
		<span class="pl-k">return</span> <span class="pl-n">go</span><span class="pl-p">(</span><span class="pl-n">root</span><span class="pl-o">*</span><span class="pl-mi">2</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">,</span><span class="pl-n">step</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">);</span>
	<span class="pl-p">}</span> <span class="pl-k">else</span> <span class="pl-p">{</span>
		<span class="pl-n">tree</span><span class="pl-p">[</span><span class="pl-n">root</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-mi">1</span><span class="pl-p">;</span>
		<span class="pl-k">return</span> <span class="pl-n">go</span><span class="pl-p">(</span><span class="pl-n">root</span><span class="pl-o">*</span><span class="pl-mi">2</span><span class="pl-p">,</span><span class="pl-n">step</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">);</span>
	<span class="pl-p">}</span>
<span class="pl-p">}</span>
<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">(){</span>
	<span class="pl-n">freopen</span><span class="pl-p">(</span><span class="pl-s">&quot;drop.in&quot;</span><span class="pl-p">,</span><span class="pl-s">&quot;r&quot;</span><span class="pl-p">,</span><span class="pl-n">stdin</span><span class="pl-p">);</span>
	<span class="pl-n">freopen</span><span class="pl-p">(</span><span class="pl-s">&quot;drop.out&quot;</span><span class="pl-p">,</span><span class="pl-s">&quot;w&quot;</span><span class="pl-p">,</span><span class="pl-n">stdout</span><span class="pl-p">);</span>
	<span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">d</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">bi</span><span class="pl-p">);</span>
	<span class="pl-kt">int</span> <span class="pl-n">bn</span><span class="pl-p">;</span>
	<span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;</span><span class="pl-n">bi</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span><span class="pl-n">bn</span><span class="pl-o">=</span><span class="pl-n">go</span><span class="pl-p">(</span><span class="pl-mi">1</span><span class="pl-p">,</span><span class="pl-mi">1</span><span class="pl-p">);</span>
	<span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d&quot;</span><span class="pl-p">,</span><span class="pl-n">bn</span><span class="pl-p">);</span>
	<span class="pl-k">return</span> <span class="pl-mi">0</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
</cpde></pre></div>